In a wireless network using half duplex frequency division duplex (HFDD), such as that permitted in a WiMAX network, a base station may have full duplex capability, i.e., the base station can transmit downlink traffic on one frequency and simultaneously receive uplink traffic on another frequency. However, some or all of the mobile stations in the network may only have half duplex capability, i.e., they can transmit on one frequency and receive on another frequency, but cannot do both at the same time. For the overall network to be efficient under these conditions, the base station should carefully schedule traffic so that it is transmitting to some mobile stations and receiving from other mobile stations at the same time, in a way that tries to minimize idle time on both uplink and downlink channels. In this regard, multicast traffic, and in particular multicast and broadcast service (MBS) traffic, may present particular problems, since large numbers (possibly all) of the mobile stations may need to be able to receive the same downlink traffic at the same time, and will therefore be unable to transmit uplink communications to the base station during that period. This can make inefficient use of the network's uplink capacity.